Texas Instruments PCM1681 User manual

DEM-DAI1681
PCM1681 Evaluation Module
User's Guide
Literature Number: SBAU137
April 2008

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Contents
3
Contents
Preface ............................................................................................................................................................7
1 Description ..........................................................................................................................................9
1.1 Functional Block Diagram ..................................................................................................................................10
1.2 EVM Description.................................................................................................................................................10
1.3 Basic Connection and Operation........................................................................................................................11
1.4 EVM Configuration Controls ...............................................................................................................................11
1.4.1 Jumper Controls .....................................................................................................................................11
1.4.2 Switch Controls.......................................................................................................................................12
1.4.3 DEM-PCM1681 Daughtercard Configuration Controls ...........................................................................13
1.5 Electrostatic Discharge Warning ........................................................................................................................13
1.6 Absolute Maximum Ratings................................................................................................................................14
2 Demonstration Software ..................................................................................................................15
2.1 Overview ............................................................................................................................................................16
2.2 Installation .......................................................................................................................................................... 16
2.3 Using the Demonstration Software.....................................................................................................................17
2.3.1 HOLD and PASS.................................................................................................................................... 19
2.3.2 Applicable Function Control....................................................................................................................19
3 Typical Performance and Measurement Examples.......................................................................21
3.1 Typical Device Performance ..............................................................................................................................22
3.2 Measurement Examples.....................................................................................................................................23
4 Schematic, PCB Layout, and Bill of Materials...............................................................................27
4.1 DEM-DAI/MDAC Schematics .............................................................................................................................28
4.2 DEM-PCM1681 Schematic.................................................................................................................................31
4.3 Printed Circuit Board Layout—DEM-DAI/MDAC ................................................................................................32
4.4 Printed Circuit Board Layout—DEM-PCM1681..................................................................................................35
4.5 Component Lists ................................................................................................................................................37
4.5.1 Bill of Materials for DEM-DAI/MDAC ......................................................................................................37
4.5.2 Bill of Materials for DEM-PCM1681........................................................................................................ 39
Important Notices ........................................................................................................................................40

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List of Figures
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1-1 DEM-DAI1681 Functional Block Diagram .......................................................................................................... 10
1-2 Jumper JP001 .................................................................................................................................................... 11
2-1 Demonstration Software Window .......................................................................................................................17
2-2 Attenuation Control.............................................................................................................................................18
2-3 Operation Control ...............................................................................................................................................18
2-4 Function Control .................................................................................................................................................18
3-1 PCM1681 Performance vs fS(Sampling Rate) and fSYS (System Clock)............................................................22
3-2 THD+N vs Input Level ........................................................................................................................................23
3-3 FFT (0 dB)..........................................................................................................................................................23
3-4 FFT (–60 dB) ......................................................................................................................................................24
3-5 FFT (–90 dB) ......................................................................................................................................................24
3-6 FFT (BPZ) ..........................................................................................................................................................25
3-7 Out-of-Band Noise vs System Clock and Oversampling Condition.................................................................... 25
4-1 Low-Pass Filter Schematic.................................................................................................................................28
4-2 Daughtercard Sockets, Connector, and Regulator Schematic ...........................................................................29
4-3 Digital Audio Interface Schematic ...................................................................................................................... 30
4-4 PCM1681 Daughtercard Schematic ...................................................................................................................31
4-5 DEM-DAI/MDAC Board Layout—Silkscreen ......................................................................................................32
4-6 DEM-DAI/MDAC Board Layout—Top (Component) Side ..................................................................................33
4-7 DEM-DAI/MDAC Board Layout—Bottom View...................................................................................................34
4-8 DEM-PCM1681 Board Layout—Silkscreen........................................................................................................35
4-9 DEM-PCM1681 Board Layout—Top (Component) Side ....................................................................................35
4-10 DEM-PCM1681 Board Layout—Bottom View ....................................................................................................36
4 List of Figures SBAU137–April 2008

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List of Tables
1-1 SW006: Data Format Selection in Hardware Control Mode for PCM1681.........................................................12
1-2 SW006: De-Emphasis and Mute Selection in Hardware Control Mode for PCM1681 .......................................12
1-3 SW001/002/003: Format Selection for CS8414 (Digital Audio I/F Receiver) .....................................................12
1-4 HDR001: Signal Path Selection for Pin 1 of PCM1681 ......................................................................................13
1-5 HDR002: Mode Control Selection of PCM1681 .................................................................................................13
1-6 EVM Absolute Maximum Ratings .......................................................................................................................14
2-1 Applicable Function Control Summary ...............................................................................................................19
4-1 Bill of Materials—DEM-DAI/MDAC..................................................................................................................... 37
4-2 Bill of Materials—DEM-PCM1681 ...................................................................................................................... 39
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6 List of Tables SBAU137–April 2008

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CAUTION
This is an example of a caution statement. A caution statement describes a
situation that could potentially damage your software or equipment.
Preface
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Read This First
About This Manual
This document provides the information needed to set up and operate the DEM-DAI1681, a test platform
for the eight-channel, 24-bit PCM1681 audio digital-to-analog converter (DAC). The PCM1681 provides a
subset of user-programmable functions through a parallel control port, in addition to a full set of
user-programmable functions through a serial control port, SPI™, or I2C™. It also contains instructions to
connect and set up the DEM-DAI1681 for operation, and for the installation and use of the software that
controls the demonstration board. For a more detailed description of the PCM1681 product line, refer to
the product data sheet available from the Texas Instruments web site at http://www.ti.com. Support
documents are listed in the section of this guide entitled Related Documentation from Texas
Instruments.
How to Use This Manual
Throughout this document, the abbreviation EVM and the term evaluation module are synonymous with
the DEM-DAI1681 evaluation module.
Chapter 1 discusses the block diagram and primary features of the DEM-DAI1681. This chapter also
provides general information regarding the default switch and jumper configurations.
Chapter 2 explains how to use the software provided with the DEM-DAI1681.
Chapter 3 presents measured typical performance and characteristic data for the PCM1681 when used
with the DEM-DAI1681.
Chapter 4 includes the EVM electrical schematics, printed circuit board (PCB) layout, and the bills of
materials.
Information About Cautions and Warnings
This document contains caution statements.
The information in a caution or a warning is provided for your protection. Please read each caution and
warning carefully.
SYS-2722 is a registered trademark of Audio Precision, Inc.
Microsoft, Windows are registered trademarks of Microsoft Corporation.
SPI is a trademark of Motorola, Inc.
I2C is a trademark of NXP Semiconductors.
TOSLINK is a registered trademark of Toshiba Corporation.
All other trademarks are the property of their respective owners.
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Related Documentation From Texas Instruments www.ti.com
Related Documentation From Texas Instruments
The following documents provide information regarding Texas Instruments integrated circuits used in the
assembly of the DEM-DAI1681. These documents are available from the TI web site. The last character of
the literature number corresponds to the document revision that is current at the time of the writing of this
User’s Guide. Newer revisions may be available from the TI web site at http://www.ti.com/ or call the
Texas Instruments Literature Response Center at (800) 477–8924 or the Product Information Center at
(972) 644–5580. When ordering, identify the document(s) by both title and literature number.
Data Sheet
Literature Number
PCM1681 Product data sheet SLES211
If You Need Assistance
If you have questions regarding either the use of this evaluation module or the information contained in the
accompanying documentation, please contact the Texas Instruments Product Information Center at (972)
644–5580 or visit the TI web site at www.ti.com.
FCC Warning
This equipment is intended for use in a laboratory test environment only. It generates, uses, and can
radiate radio frequency energy and has not been tested for compliance with the limits of computing
devices pursuant to subpart J of part 15 of FCC rules, which are designed to provide reasonable
protection against radio frequency interference. Operation of this equipment in other environments may
cause interference with radio communications, in which case the user at his own expense is required to
take whatever measures may be required to correct this interference.
Trademarks
All trademarks are the property of their respective owners.
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Description
11
1.1 Functional Block Diagram........................................................................ 10
1.2 EVM Description........................................................................................ 10
1.3 Basic Connection and Operation ............................................................ 11
1.4 EVM Configuration Controls .................................................................... 11
1.5 Electrostatic Discharge Warning............................................................. 13
1.6 Absolute Maximum Ratings ..................................................................... 14
Chapter 1
SBAU137–April 2008
Description
The DEM-DAI1681 is an evaluation board for the PCM1681, a 24-bit, 192-kHz, 8-channel audio DAC with
digital audio receiver, 8-channel second-order post filter, mode control interface to a personal computer
(PC), and various switches and jumpers for configuration controls.
The DEM-DAI1681 operates from 5-V and ±15-V analog power supplies with an S/PDIF input signal.
Project collateral discussed in this user’s guide can be downloaded from the following
URL: http://www.ti.com/lit/zip/SBAU137.
Topic Page

10
Description
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DEM-DAI/MDAC Motherboard
Ch 7
Ch 8
External-I/F
(CN004)
Ch 5
Ch 6
Ch 3
Ch 4
DAC
PCM1681
CLKO
BCLK
LRCK
DATA1
DATA2
DATA3
DATA4
DAI
(Bus)
Select
DIR
Ch 1
Ch 2
2nd-order LPF
L/R
-ch OPA2134
(fC = 54 kHz)
L/R
-ch 2nd-order LPF
OPA2134
(fC = 54 kHz)
L/R
-ch 2nd-order LPF
OPA2134
(fC = 54 kHz)
L/R
-ch
2nd-
order LPF
OPA2134
(fC = 54 kHz)
(DEM-1681
Daughtercard)
CS8414
Coax
and
Logic
SCLK
OPT
JUMPER
Format Control
+5 V
3.3 V
REG
SW006
Mode Control Interface to PC
ML MC MDI RST MDO
GND+5 V −15 V GND+15 V
M2, M1, M0
Functional Block Diagram www.ti.com
1.1 Functional Block Diagram
Figure 1-1 illustrates the functional block diagram of the DEM-DAI1681.
Figure 1-1. DEM-DAI1681 Functional Block Diagram
1.2 EVM Description
The DEM-DAI1681 EVM is shipped with the following items:
•EVM Motherboard: DEM-DAI/MDAC
•EVM Daughtercard: DEM-PCM1681
•CD-ROM containing application software, a copy of this user's guide, and a PCM1681 product data
sheet
If any of these items are missing or damaged, please contact your local Texas Instruments representative.
This EVM consists of two PCBs. The DEM-DAI/MDAC motherboard is a common PCB for similar devices
such as the DEM-DAI1608 and the DEM-DAI1680. The DEM-PCM1681 daughtercard contains the
PCM1681 DAC device, as shown in Figure 1-1.

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Description
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www.ti.com Basic Connection and Operation
1.3 Basic Connection and Operation
•Set/confirm jumper JP001 to provide the system clock and other digital signals from the digital audio
receiver to the PCM1681.
•Set/confirm jumper JP201–JP224 to select the cutoff frequency of the second-order post low-pass filter
(LPF) for DAC outputs.
•Set/confirm jumper HDR002 and HDR001 of the PCM1681 daughtercard to select mode control and
coressponding primary pin function.
•Connect the +5-V and ±15-V power supplies to VCC, AVCC, –AVCC, and GND on connectors
CN051–CN055.
•Connect the S/PDIF signal into CN001 (COAX) or U001 (OPT).
•Connect the PC printer port to CN003 for mode control, if required.
•Set/confirm the input data format using SW001–SW003 and SW006 (H/W control mode) or the
demonstration software (S/W SPI control).
1.4 EVM Configuration Controls
1.4.1 Jumper Controls
The following jumpers are provided onboard for configuration controls:
•JP001: Set Interface of Digital Signal from DIR to DAC (the device under test [DUT])
The digital signal generated by the digital interface receiver (DIR) is input to this jumper. For each
shorted pin, the corresponding digital signal is applied to the PCM1681. All signals except for BCK and
BCK [L/J] must be shorted for normal operation using the DIR; for BCK and BCK [L/J], one or the other
must be shorted according to the data format selection of the DIR. Figure 1-2 shows jumper JP001.
JP001
SCLK
CLKO
GND
BCK
BCK [L/J]
LRCK
DATA1
DATA2
DATA3
DATA4
Figure 1-2. Jumper JP001
•JP201–JP224 (24 Pieces): Set fC(Corner Frequency) Selection of Second-Order Post LPF
These jumpers determine the corner frequency (fC) of the second-order post low-pass filter.
– JP201–JP224 shorted: fC= 54 kHz for BW = 20 kHz
– JP201–JP224 open: fC= 108 kHz for BW = 40 kHz

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Description
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EVM Configuration Controls www.ti.com
1.4.2 Switch Controls
The following switches, summarized in Table 1-1 to Table 1-3, are provided onboard for EVM control.
Table 1-1. SW006: Data Format Selection in Hardware Control Mode for PCM1681
FMT1 (as S4/ML) FMT0 (as S1/RST) Data Format Selection
On (L) On (L) 24-bit, Right-Justified Format
On (L) Off (H) 16-bit to 24-bit, I
2
S Format
Off (H)
On (L)
16-bit to 24-bit, Left-Justified Format
Off (H) Off (H) 24-bit, I
2
S Mode TDM Format
Table 1-2. SW006: De-Emphasis and Mute Selection in Hardware Control Mode for PCM1681
MUTE (as S2/MDI) DEMP (as S3/MC) De-Emphasis and Mute Selection
On (L) On (L) Mute Off, De-Emphasis Off
On (L) Off (H) Mute Off, De-Emphasis 44.1 kHz On
Off (H) On (L) Mute On, De-Emphasis Off
Off (H)
Off (H)
Mute On, De-Emphasis 44.1 kHz On
Table 1-3. SW001/002/003: Format Selection for CS8414 (Digital Audio I/F Receiver)
SW003 (M2)
SW002 (M1)
SW001 (M0)
Data Format Selection
L L L 16-bit to 24-bit, Left-Justified
(1)
L H L 16-bit to 24-bit, l
2
S
H L H 16-bit, Right-Justified
(1) BCK of JP001 selection. When Left-Justified data format is used, move the jumper from BCK to BCK [L/J] for the JP001 setting.
SW004: Manual reset for CS8414
SW005: Digital Audio Interface Selection
•Internal—CS8414
•External—(CN004)

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Description
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www.ti.com Electrostatic Discharge Warning
1.4.3 DEM-PCM1681 Daughtercard Configuration Controls
This section discusses the headers that are provided as configuration controls for the PCM1681
daughtercard.
1.4.3.1 HDR001: Select Signal Path for Pin 1 of PCM1681
Either 1-2 or 3-2 must be shorted according to the function of pin 1 of the PCM1681, which is determined
by the HDR002 setting. Table 1-4 summarizes the select signal path configuration for HDR002.
Table 1-4. HDR001: Signal Path Selection for Pin 1 of PCM1681
HDR001
Signal Path for Pin 1 of PCM16811-2 3-2
Short Open Path for ZR1 output for S/W (SPI and I
2
C) Control Mode
Open Short Path for FMT0 input for H/W Control Mode
1.4.3.2 HDR002: Select Mode Control of PCM1681
Either 1-2, 3-4, 5-6, or 7-8 must be shorted in order to select mode control type and oversampling
condition of the PCM1681. Table 1-5 summarizes the mode control selection configuration for HDR002.
Table 1-5. HDR002: Mode Control Selection of PCM1681
HDR002
Mode Control of PCM1681
1-2
3-4
5-6
7-8
Short Open Open Open S/W (I
2
C) Control Mode
Open Short Open Open H/W Control Mode with Narrow Band Operation
Open Open Short Open H/W Control Mode with Wide Band Operation
Open
Open
Open
Short
S/W (SPI) Control Mode
1.5 Electrostatic Discharge Warning
Many of the components on the DEM-DAI1681 are susceptible to damage by electrostatic discharge
(ESD). Customers are advised to observe proper ESD handling precautions when unpacking and handling
the EVM, including the use of a grounded wrist strap at an approved ESD workstation.
CAUTION
Failure to observe ESD handling procedures may result in damage to EVM
components.

14
Description
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Absolute Maximum Ratings www.ti.com
1.6 Absolute Maximum Ratings
Table 1-6 summarizes the absolute maximum ratings for the DEM-DAI1681 EVM.
Table 1-6. EVM Absolute Maximum Ratings
Parameter
DEM-DAI1681 EVM
UNIT
MIN TYP MAX
Power Supplies
5-V Power supply CN054
+6
V
±15-V Power supply CN051/3 ±18 V
Signal Inputs
S/PDIF input CN001
±2 V
PC interface input CN003 0 4 V
Signal Outputs
Line outputs CN201 to CN208
±
4
V

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Demonstration Software
15
Chapter 2
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Demonstration Software
This chapter provides information regarding the software that is provided with the DEM-DAI1681. The
software allows programming of the PCM1681 internal registers.
Topic Page
2.1 Overview..................................................................................................... 16
2.2 Installation.................................................................................................. 16
2.3 Using the Demonstration Software ......................................................... 17

16
Demonstration Software
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Overview www.ti.com
2.1 Overview
Use the demonstration software on a personal computer (PC) or lab PC that meets the following
requirements:
•Equipped with Microsoft® Windows® operating system (Windows XP or earlier)
•Available printer port
•CD-ROM drive
2.2 Installation
First, connect the PC printer port to CN003 on the DEM-DAI1681 using a standard printer cable.
Next, install the demonstration software. The software is distributed on a CD-ROM that is shipped with the
DEM-DAI1681. The software is also available for download from the DEM-DAI1681 product folder at
www.ti.com.
To install the software on the PC, first create a new folder on your hard disk drive with an appropriate
name (such as DEM1681). Next, load the CD-ROM into the PC, and navigate to the DEM1681 folder on
the CD-ROM. Copy all the files in the DEM1681 directory to the new folder on the PC.
Open the configuration setting file named dem1608.ini using a text editor, such as Notepad or WordPad.
When the file is open, search for the following command line:
PCMIFADR = &h378
The address &h378 indicates the printer port address that the demonstration software uses to
communicate with the DEM-DAI1681. This address must be set to &h378, &h278, or &h3BC. Most PCs
use &h378 as the default printer port address. If your printer port is not located at &h378, edit the address
to correspond with the PC printer port address.

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Demonstration Software
17
Using the Demonstration Software
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2.3 Using the Demonstration Software
Open the working directory you created on the PC (see the Installation section). Double-click on the
application file named dem1608.exe. A window appears on your desktop screen, as shown in Figure 2-1.
There are two menu selections (Execute and Window) in the menu bar near the top of the window.
Figure 2-1. Demonstration Software Window
The Execute menu includes three selections:
•Initialize instructs the program to write almost of the PCM1681 internal registers with the default values
•Reset instructs the program to rewrite the PCM1681 internal registers with the data currently selected
in the application window
This window and function is not applicable on the PCM1681:
•Exit closes the application
The Window menu includes five options:
•Attenuation control (see Figure 2-2): enables users to control PCM1681 digital attenuation level by
changing the slider position for each channel.
•Operation control (see Figure 2-3): allows users to control mute on/off and DAC operation
enable/disable by channel.
•Function control (see Figure 2-4): controls various programmable functions, such as Interface formats,
oversampling mode, DAC output phase, de-emphasis function/frequency, and so forth. Some functions
are not available for the PCM1681; see Table 2-1 for details.
These windows and functions are not applicable on the PCM1681:
•GPO control
•Register read

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Demonstration Software
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Using the Demonstration Software
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Figure 2-2. Attenuation Control Figure 2-3. Operation Control
Figure 2-4. Function Control

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Demonstration Software
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Using the Demonstration Software
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2.3.1 HOLD and PASS
Near the top of each window, there is a small button. This button is labeled either HOLD or PASS. You
can toggle the current setting by clicking on this button. When set to HOLD, the settings in an active
window can be changed, but are not written to the register(s) until you press the OK button that appears at
the bottom of the screen.
When the button is set to PASS, any setting changes made in an active window are immediately written to
the corresponding register(s).
2.3.2 Applicable Function Control
Table 2-1 summarizes the various functions of the DEM-DAI1681 and the default settings for each
function. Note that the software is also designed to control the DEM-DAI1608 as well as the
DEM-DAI1681; therefore, there are several inconsistencies between the demonstration software and the
PCM1681 register definitions. Table 2-1 also describes these differences between the software of
DEM-DAI1681 and PCM1681 in detail.
Table 2-1. Applicable Function Control Summary
Function
PCM1681 Default Setting
Availability on DEM-DAI1681
Digital Attenuation Control, 0 dB to –63 dB
in 0.5-dB Steps
0 dB, No Attenuation
Applicable
Soft Mute Control Mute Disabled Applicable
DAC1–8 Operation Control DAC1–8 Enabled Applicable
Audio Data Format Control 16-Bit to 24-Bit Left-Justified Partly Applicable
(1)
Digital Filter Roll-Off Control Sharp Roll-Off Applicable
De-Emphasis All Channel Function
Control
De-Emphasis All Channel Disabled
Applicable
De-Emphasis All Channel Sample Rate
Selection
44.1 kHz
Applicable
Output Phase Select Normal Phase Applicable
Zero Flag Polarity Select High Applicable
Software Reset Control Reset Disabled Not Applicable
Output Phase Select per Channel
Reverse Phase
Not Applicable
Oversampling Rate Control
Narrow (x64, x32, x16) mode
Applicable
Digital Filter Roll-Off Control per DATA
Group
Slow Roll-Off Not Applicable
Zero Flag Combination Select ZR1: DATA1 Lch
ZR2: DATA1 Rch
Not Applicable
Digital Attenuation Mode Select 0 to –63 dB, 0.5-dB step Not Applicable
Zero Detect Status
(Read-only, I2C Interface Only)
Not Applicable Not Applicable
Function
DEM-DAI1681 Default Setting
Availability on PCM1681
SCKO Frequency Selection and Output
Enable Control
Enabled as SCKO = SCKI Not Applicable
GPO Output Set and Control Enabled as Zero Flags, not GPOs Not Applicable
Register Read and Address Control Enabled without Auto-Increment Not Applicable
(1) There is a difference betwen applicable formats and default setting.

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20 Demonstration Software SBAU137–April 2008